This would be a really good premise if the mc was better. I don't know about you guys, but I think he is doing a terrible job of switching his mental state from 'I live in polite society' to 'We live on an island with a bunch of crazy assholes and these 5 girls are relying on me to keep us all alive and safe'.
I'm self-aware enough to know that most men overestimate how useful they are in these situations, but I am at least confident that I would have long ago put my mind to killing those psychopaths on the other side of the island. You don't gotta kill all of them, just the few at the top of the hierarchy that are pushing their crazy shit onto everyone.